Cellulose is widely found in aleurone layer and cell wall of barley, wheat, corn, rice and sorghum, a linear molecule connected by glucose through the beta-1,4-glycoside bond, accounting for about 40% of the dry weight of cells. Cellulase can be produced from a variety of microorganisms, including fungi, actinomycetes, sticky bacteria and real bacteria, and can be produced by plants. The most recent studies were focused on cellulase, which are mainly derived from fungus.
Cellulase were widely used in various industry such as food, feed, beer, medicine, textiles and bioenergy. The different industrial applications required different properties. For example, feed industry needed acidophilus cellulase, but textile industry needed high temperature and alkali cellulase. The cellulase widely used was from Trichoderma viride, had optimum pH value of around 5.0, and optimum temperature between 50 to 60° C., and can't meet the requirements of water washing finishing industry and paper pulp making industry because cotton fiber was tolerant to alkali but not tolerant to acid. And, thermostable cellulase will be more advantageous, since heat resistance can increase the rate of reaction, decrease the viscosity of the substrate, and inhibit the contamination of the bacteria. Therefore, it's of great significance to investigate the high-temperature neutral cellulase which is alkali resistant.